Barometric device



July 10, 192s.

l. l. EREMEFF BAROME TRI C DEVI CE Filed July 25. 1921 2 sheets-snee;

ma l WS Jilly -l0, 1928.

l. l. EREMEEFF BABOMETRIC DEVICE 2 sheets-Sheet .2

Filed July 23. 1921 63 fz I f/ Patented' July 1o, 192s.' Y

l UNITE STATES Ivm 1..,EREMEEFF, or DAYTON, oHIo.

BABOMETBIC DEVICE.

Application mela July 23,

This invention relates generally to a barometric device and more particularly to an instrument of this type which is intended to indicate small differences of altitude on a magnified scale.

The particular embodiment of the invention described herein is provided with a sensitive mechanism responsive to slight changes in atmospheric pressure and with multiplying devices for indicating the extent of movement of the mechanism.

This invention' also aims to provide means for temporarily connecting the mechanism responsive to changes in pressure to the atmosphere so that any desired elevation may be selected as a datum.v

Other objects of the invention, consisting of novel features of construction and arrangements of parts, will become apparent on reference to the subjoined specification which describes the invention in connection with the accompanying drawings,

In the drawings:

Figure 1 is a central vertical section through the barometric device;

Figure 2 is a front elevation of the indicating means;

Figure 3 is a front elevation of the instrument case with the front plate removed;

Figure 4 is a side elevation with certain parts shown in vertical section, of a modified form of my invention; and

Figure 5 is a plan view of this modified form showing the indicating dial.`

Like numerals of reference indicate corresponding parts throughout the several views of the drawings. l

The numeral 10 designates generically a thermally insulated casing having the outer shell 11 and the inner shell 12 spaced therefrom and adapted to contain fluid under constant pressure for a given datum. The space between these shells is preferably illed with a substance 13 whichis a poor conductor of heat,l such as felt. This casing is provided at the top with an opening which pierces both'of the shells, and a tube 14 is inserted in this opening and is provided with a flange 15 which .is adapted toabut against the outer shell 11 in air tight relation thereto.

An instrument l.case 16 is mounted in a suitable annular bracket 17 which is secured to the dash or instrument board 18 of an aircraft or motor vehicle by means of screws 19. This bracket is formed with a depend- 1921. Serial N0. 487,143.

ing annular flange 2O and the instrument case 16 is inserted through the rear end of ple 23, an air chamber 24 andan air duct 25 which passes through the nipple. The passage 25 and the chamber 24 communicate at their inner ends with a central opening or conduit 26 which is adapted to communicate with the interior of a suitable pressure responsive device herein illustrated in the form of a bellows 27. The bellows is located within the instrument case 16 and is attached at its lower end to the base 22 concentrically about thc conduit 26. The air chamber 24l communicates near its outer .end with a conical passage 28 controlled by a slidable, conical valve 29. The valve 29 is formed with an outwardly extending stem 30 which vpasses-through an aperture in the flange 20;

The outer end of this valve stem is equipped with a knob or handle 31 whereby the valve may be conveniently operated against the tension of a coil spring 32 which is compressed between the flange 20 and the conical plug of the valve 29 and thus normally tends to retain the Valve upon its seat.

.Opposite walls of the instrument case 16 areprovidedlwith plugs 33, 34, one or both of which may be detachably mounted therein. These plugs are formed with central apertures which are adapted to receiveh the reduced outer ends of a shaft 35 so that the. latter is `rotatably mounted in bearings thus formed in the plugs 33, 34. A iiexible connection such as a chain 36 is secured at one end to the shaft 35 and at the other end to a loop 37 secured to the cover plate Aof the bellows.

Near one end of the shaft 35 a gear set, composed of a small gear 38 and a large gear 39, is secured. A flexible connection such asa chain 40 is wound upon the shaft 35 in a direction opposite from chain 36, and the lower end of this chain 40 is connected to one end of a spring 41.l the other.end of which is fastened to a hook 42 projectingv outwardly from a partition wall 43. This partition wall divides the instrument case containing thepressure responsive device and the other containing the transmitting'gear-y ing, someof which is above described. An aperture 44 is formed in the front wall of the instrument case and telescopingv shafts consisting of the inner shaft 45 and the -outer shaft 46 are rotatably mounted in this aperture: The shaft 45 carries the long indicating hand 47, and the shaft 46 carries the short indicating hand 48. In order that the hands 47 and .48 mayA have the correct relative motion, they shafts 45 and 46'carry, res ectively, the gears 49 and 50, which mesh wit lthe larger gear 39 and the smaller gear 38.v The front plate is provided with a suit` able dial 51 and acover glass 52 is placed over the indicating hands and the dial andv is retained in place by the de e ding flange of the sup orting bracket 1%. The gearing is preferab y arranged so that the large hand will make four revolutions to one revolution of the small hand.v

-Theinstrument case 16 is provided with a suitable vent 53 so that the pressure within the case will at all times be equal to the prevailing atmospheric pressure. In order to restore the indicating means to zero position and to damp oscillations of the same, springs l to the bellows 27.

When it is desired to use a certain elevation as a datum, the valve 29 is opened so that the pressure within the bellows and casing 10 becomes equalized with the atmospheric pressure. This is the zero indication of' the mechanism. The valve 29 is then permitted yto close and as the device ascends, the bellows 27 will expand owing to the decreased pressure in the instrument case. The shaft 35 is then caused to turn by the spring 41 andthe gearing is operated for moving the hands 47 and 48 in the proper ratio. After the bellows have been expanded to the limit of their design, or after the long hand has made four revolutions, the valve 29 may again be opened and further yelevations obtained with reference to this hew datum. In the case of descent, the bellows 27 will contract and exert a tension stress upon chain 36 whereby the shaft 35 lis turned in opposition to spring 41. v

In Figures 4 and 5, a 'slightly modied form of the invention is shown in which an ordinary thermos bottle 60 is provided with' astopper 61 formed with two parallel passages 62 and 63 in which suitable tubes have beeninserted. The stopper 6l is -mounted in a recessformed in the bottom of a suplof transparent material so nevegaaa porting plate or strip 64 and the top surface of` this strip is formed with an vannular. depression'zin which is 'mounted the serte in the passage 62 pierces the base plate 65 vand thuscommunicates with the interior 'of the bellows. This tube is preferably 63 by a suitable air tight connection 69. An

base (plate 65 of a bellows 66. The tube in aperture pierces the plate 64 and the tube '68 in spaced relation to the connection 69,

and a valve 7l is slidably mounted in the tube 68 to controlthe communication between the vent 70 and the interior ofthe thermos bottle 60. In order to limitthe motion'of the valve 71 a suitable shoulder is formed in the tube 68 by reducing the diameter of its boreand a valve stem 72. extends through this reduced bore and is connected at its outer end with a knob, 7 3 for convenience ot' operation. ring 76 which islmounted on the plate 64. These posts extend upwardly on 'opposite Posts 74 and 7 5 are secured to a sides of the bellows 66 and a bell crank lever 77 is pivoted to the upper end of the post 7 5 by a stub shaft 7\8. 'A spring 79 is con- Vnected at one end tothe post" 74, at the other end to a link 80, vand intermediately it is connected to the coder plate of the. bellows. The link 8O is pivoted at one end to one arm ofthe bell crank lever 77. A dial plate 81 has a sleeve extension 82, by means of which .it ismounted upon the upper end of the post 74. A plate 83 is secured to the post 74 in spaced relation to the dial plate and a bent plate 84 is secured to the plate 8 3 and has an arm projecting in 'space'd relation thereto. A shaft 85 extends through an opening in the dialplate and an aligningaperture in the ar'r'n of plate -84 and abuts at its lower end against the plate 83. The shaft 85 is rotatably mounted in the bearings thus provided and is equipped at its upper end with an indicating hand 86. A coil sprin 85 is connected at one end tothe shaft an at the other en d to the plate 83. Sha/ft 85 has attached thereto 'a small sprocket wheel or pulley 87 and a chain 88` is secured at 'one end to the pulley and at the other end to the long arm of the bell crank lever 77. A vent 89 is provided in the .supporting strip64 in order to maintain atmospheric` pressure Within the casing 90 which contains the bellows 66. The casing 90 is referably made tliat the readin s indicated by the hand 861`ay be -r'eadi y visible. y ,y f

This forni of my invention Ioperates simoyclveisthenclosedso I plied to greater intensa ilarly to the form ilmtrated in 1,* said instrument ease, seid bellows and 3. Thevalve'a'lisfirstopen iuorder to obtain the prevailing annospheric pressure within the thermos bottle and bellows. This to shut o communication between the osphere and the interior of thethermos bottle andbellows. As the aircraft or motor vehicle seconds, the belows will expand and act upon thespring 79 so :is tooctuate heil crank 'N'which through the medium of chain 88 actuantes shaft 85 and the indicating hund 86.

The apparatus of this invention is intended primarily tar-indicate relatively smell differences in elevation such :$4,000 feet but it hennderstood thnt itmny aisobe apin= altitude, depending-oi course,'nponthe design of the pressure responsive menno and the ratio between the movement of the pressure lresponsive means and the indicating device. The apparatus may also he used as :n simple barometer to indicate vweather conditions. When monnted en n motor vehicle the device may he used in connection with :n

chart or other recor mechanism to indiente the topography o the lzindrtrnversed by the vehicle.-

Itis evident that those skilled in the ort to which this invention'appertains man; vary the details of construction, as well :is the nrrangement of paris, without deparng from the spirit Aof the invention, andtherefore I appended claims. c

do not wish to be limited to the above disclosure except as maybe by the I claim: v 1. An instrument of the ciass described, comprising in combination a. an instrmpent case having e ventcommunicating with the atmosphere, pressure responsive bellows within said instrument case, saidV bellows being attached to said instrument case on one end, the other end whereof is movable in response to variationsin` the support aorded thereto by the internal pressure of said bellows against atmosiheric pressure, means-forming :a communicative passge between the interior of said casing and the interior of said bellows, mechanism in the instrument case for indicating the extent of movemenboi said bellows and a normall'y closed valve adapted to beopened to afford communication between the atmosz phere' and sai means and the interior of said bellows.

2. An instrument of the class described comp-isinr the combination with an instrument a. vent communicating withV the atmosphere, pressure responsive bellows being attached instrrmlent case on one end, the other end whereof is nuovzrhleA in rponse to variations in the support efforce...

sai owe mtmosp eric rassure c shaft rotatabiymounted in said cgse, a. crinby the internal pressure of nection between seid bellows and shaft ier .A rotating said in one direction,spring vdevices tending to retnrn the shat to normal position, en indicating device, and

transimtting mechanism between seid shaft and said device, of n casing, means forming a. commnniccve passage hetween the interior of said casing adopted to contain timid onder premere and the other end of bellows and valve means snidvpessnge and the atmosphere.

3. An instrument of the class described comprising the combination mentiroso having a. vent communicating nsive bellows the atmosphere, pressure within seid cese, e. rotatable shalt within seid instrument cese, an A'indicating device therefor, s connection between seid bellows and shaft for rotehng said in one direction, sp w actuated tending to rotate seid shnit in the other direction for transmitting relative motion of seid pressure responsive bellows to snid indicating device, of a. casing,n member n. pasf sage therethrn and the interior of said withinteriooii said pressure responsive bellows,Q and valve means for opening and closing communication between the atmosphere and the interior of seid pressucre responsive bellows and seid casing respectively.

4. in am instrument of the class described comprising in combination, en instrument Sit case, e pressure responsive bellows therein, a thermally insulated casing, e member pro- .and said casing to. the atmosphere at de sind intervals, a rotatable shaft, a connection between said slioft'nd said bellows for rotating said shaft in one direction or the other depen r upon the expansion or contraction of sai bellows,'spr1ng devices exleterally from said bellows for returning the latter to normal position, an indicating device and transmitting mechanism in the instrument case and between said shaft Vand indicatingdevic.

In testimony whereof I have axed my signature.

' IVAN I. EREMEEFF. 

